const isDevice = function () { // 判断是android还是ios还是web
    var ua = navigator.userAgent.toLowerCase()
    if (ua.match(/iPhone\sOS/i) === 'iphone os' || ua.match(/iPad/i) === 'ipad') { // ios
        return 'iOS'
    }
    if (ua.match(/Android/i) === 'android') {
        return 'Android'
    }
    return 'Web'
}   